I never said wookieepedia was a always right, it was just another source.

Discarding all EU and personal assumptions we are left with what little we know about Vaders suit and injures from the movies...

Vader (around ROTJ):

mechanized replacements for both of his arms and his legs at the knees
respiratory system is at least partially mechanized
the lung tissue remaining (if any) is damaged
body is mostly covered in partially healed 2, 3, and 4 deg. burns
fractured skull, (partially healed)

(this is not counting hypothetical or EU injures; no starkiller beating, no loosing hand for destruction of death star, no jedi hunting...)

If his powers remained intact these injures surely would at least slightly weaken him.

I also tend to disregard the costume differences, things change between movies, the imperial rank plaques and different in each movie, the species makeup of the rebel alliance, the whole luke-leia thing. Minor costume changes are not meant to be taken literally, its just a costume...a cool one, but a costume.